On 07/15, Paul E. McKenney wrote: > > On Wed, Jul 15, 2015 at 09:36:01PM +0200, Oleg Nesterov wrote: > > > > Do you mean you need another user except percpu_rw_semaphore? I do > > not see any right now... > > Not asking for more than one use, but it does need a use. I believe > that percpu_rw_semaphore suffices. > > > Let me remind about sb_writers again. It actually has 3 rw_sem's > > and I am trying to turn then into percpu_rw_semaphore's. > > > > In this case freeze_super() will need 6 synchronize_sched_expedited(). > > This just looks ugly. But if we have rcu_sync primitives, all 3 sem's > > in struct super_block can share the same "struct rcu_sync", and > > freeze_super() will need only once synchronize_sched(). > > Makes sense.
Great, thanks. And iiuc Linus doesn't object to this particular change. Plus I see the "Make checkpatch.pl warn on expedited RCU grace periods" patch ;) So can I assume you will take these changes? I do not need them right now, just I need to know what should I do in destroy_super() and (much more importantly) what should I say in the changelogs if I try to convert sb_writers to use percpu_rw_semaphore. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
